CN101345616B - Communication encryption and decryption method of four-item weight score Fourier transform based on multi-parameter - Google Patents

Abstract

A communication encryption and decryption method based on multi-parameter tetrachoric weighted score Fourier transform relating to communication technology field. The invention can disarrange constellation distribution and disenable non communication target to intercept and detect communication signal. The inventive method comprises that data source is modulated at transmitter by base band to deliver to encipher module which executes tetrachoric weighting score Fourier transform controlled under dynamic encryption parameter alpha, dynamic encryption vector MV and NV , and digital carrier modulation, then enciphered data is delivered to channel for transmitting after D/A conversion and up converter; data collected by down converter and A/D is delivered to decryption module for digital carrier coherent demodulation, deciphered data is obtained after tetrachoric weighting score Fourier transform controlled by dynamic deciphered parameter alpha, dynamic deciphered vector MV and NV, then base band demodulation is operated. The invention is suitable for secure communication device for existing communication fields.

Description

Communication encryption and decryption method based on multi-parameter four-item weight class fractional Fourier transform

Technical field

The present invention relates to the signal processing of fractional Fourier transform and secret, the decryption method of communicating by letter, belong to communication technical field.

Background technology

The extensive use of modern communication technology has become the person's of stealing secret information dreamboat.In the communications field, it is fierce unusually with anti-struggle of stealing secret information to steal secret information.Communication is stolen secret information technology in development, and the communication security technology is also in development.The main cause that causes communication to divulge a secret is that communication security is backward in technique.

So-called secure communication in order to prevent that the communication technology is stolen, is taked hidden means to secret information and transmission means thereof exactly, thereby is reached secret purpose in communication process.Secrecy technology mainly divides two aspects, i.e. channel security technology and information secrecy technology.The channel security technology, exactly that the transmission of Information approach is hidden or protect, make the stranger not intercept and capture needed secret information from channel.The information privacy technology is changed, is pretended information transmitted exactly and hidden, even this like this information is intercepted and captured, also can't learn its true content.

Typical secure communication can be divided into three links: the one, and the information source protection, very fragile when information source information is being exposed with primitive form, be stolen easily, its protection is called the information source protection; The 2nd, information protection promptly takes measures raw information to make that it is changed beyond recognition, can not recognize through handling and encrypting, though the signal after handling and encrypting received by illegal recipient, be difficult to but will take out the represented original contents of information; The 3rd, signal protection, the overall process that the information after promptly encrypting enters transmission medium is exactly to hide signal to this link protection, makes the other side be difficult to capture, thereby loses the possibility of deciphering.

(Weighted FRFT is a kind of new mathematical tool that is different from classical fractional Fourier transformation WFRFT) to weighting class fractional Fourier transform, is again the mathematic(al) manipulation method that is different from a kind of renewal of classical fractional Fourier transformation.WFRFT is not applied in the communications field at present.The four-item weight class fractional Fourier transform (4-WFRFT) that Equation Section (Next) is traditional is defined as:

F ^α[f](t)＝a ₀(α)f(t)+a ₁(α)F(t)+a ₂(α)f(-t)+a ₃(α)F(-t)

A wherein ₀～a ₃Be the weight coefficient by the control of dynamic encryption parameter alpha, the form of embodying is:

${\mathrm{\α}}_l\left(\mathrm{\α}\right)=\cos \left(\frac{(\mathrm{\α}-l)\mathrm{\π}}{4}\right)\cos \left(\frac{2(\mathrm{\α}-l)\mathrm{\π}}{4}\right)\exp (\±\frac{3(\mathrm{\α}-l)\mathrm{\πi}}{4}),$ (l＝0，1，2，3)

The value cycle of dynamic encryption parameter alpha is 4, and the span of setting α here is any real number between [0,4] or [2,2], for the real number outside the span, and weight coefficient a _l(l=0,1,2,3) will present cyclic variation along with α.The result of four-item weight class fractional Fourier transform is f (t) when α=0, and the result of four-item weight class fractional Fourier transform is F (t) when α=1.Wherein f (t) is the function that is transformed, and f (is the counter-rotating function at center with the initial point for f (t) t); F (t) becomes the right function of Fourier transform with f (t), and F (is the counter-rotating function at center with the initial point for F (t) t).Fourier transform adopts following definition:

$X\left(\mathrm{\ω}\right)=\frac{1}{\sqrt{2\mathrm{\π}}}\underset{-\∞}{\overset{\∞}{\∫}}x\left(t\right)e^{-\mathrm{j\ωt}}\mathrm{dt},$ -∞＜ω＜∞

The four-item weight class fractional Fourier transform of the discrete series after promoting is defined as follows:

F ^α[x(n)]＝w ₀(α)x(n)+w ₁(α)X(n)+w ₂(α)x(-n)+w ₃(α)X(-n)

Wherein $w_l\left(\mathrm{\α}\right)=\frac{1}{4}\underset{k=0}{\overset{3}{\mathrm{\Σ}}}\exp \{\±\frac{2\mathrm{\πi}}{4}[({4m}_k+1)\mathrm{\α}(k+{4n}_k)-\mathrm{lk}\left]\right\}$ l＝0，1，2，3

Be by α, MV=[m ₀, m ₁, m ₂, m ₃] and NV=[n ₀, n ₁, n ₂, n ₃] wait the common weight coefficient form of controlling of 9 parameters, wherein MV and NV are real vector.When MV and NV be 0 and the time, w _lWith a _lDefinition coefficient equivalence.X (n) and X (n) be discrete Fourier transform (DFT) (DFT) to (through substitution of variable n=k), DFT adopts following formal definition:

$\left\{\begin{array}{c}X\left(k\right)=\frac{1}{\sqrt{N}}\underset{n=0}{\overset{N-1}{\mathrm{\&Sigma;}}}x\left(n\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H2008101369395E00031.png,H2008101369395E00041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}}{N}\mathrm{kn}}\\ x\left(n\right)=\frac{1}{\sqrt{N}}\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}X\left(k\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="H2008101369395E00031.png,H2008101369395E00041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j\end{array}\right.$

Four-item weight class fractional Fourier transform after promoting has been inherited all character of former conversion, can come the rotation of the periodicity and the characteristic vector of control change in addition by the adjustment to real vector M V and NV.In a word, the four-item weight class fractional Fourier transform after promoting is complicated more, but more complete in theory, and is more flexible and changeable during practical application.

Summary of the invention

The purpose of this invention is to provide a kind of communication encryption and decryption method,, make non-communication objective person be difficult to intercept and capture and detect signal of communication to upset former baseband signal constellation based on multi-parameter four-item weight class fractional Fourier transform.

Method of the present invention realizes by following step: at transmitter terminal, data source is fed to encrypting module through after the baseband modulation, encrypting module carries out multi-parameter four-item weight class fractional Fourier transform to obtain enciphered data to data under the control of dynamic encryption parameter alpha and dynamic encryption vector MV, NV, send into channel again after D/A conversion and up-conversion through the enciphered data after the digital carrier modulation and transmit; At receiver end, be sent to deciphering module through the data after down-conversion and the A/D sampling, in deciphering module, at first carry out digital carrier coherent demodulation, then after multi-parameter four-item weight class fractional Fourier transform through dynamic deciphering parameter-α and dynamically deciphering vector MV, NV control, receive data and obtain deciphering, carry out base band demodulating work then; The concrete steps of encrypting are: the signal to be encrypted that, becomes plural form after the binary data process baseband modulation that data source provides gives encrypting module to encrypt; Two, encrypting module is encrypted data frame by frame, and frame length is the length of discrete Fourier transform (DFT); The core of encrypting promptly is weighted summation to the data sequence, and four sequences that are weighted are followed successively by: the sequence after the sequence after the be-encrypted data sequence of input, the be-encrypted data sequence process discrete Fourier transform (DFT), the be-encrypted data sequence process counter-rotating module, be-encrypted data sequence are successively through the sequence after discrete Fourier transform (DFT) and the counter-rotating module; User's Dynamic Selection dynamic encryption parameter alpha and dynamic encryption vector MV, NV, and by coefficient generation module generation weight coefficient w ₀, w ₁, w ₂, w ₃, be weighted summation to being weighted sequence; Three, the sequence of complex numbers after the weighting is carried out digital carrier modulation back output, be the sequence after the encryption; The concrete steps of deciphering are: the coherent demodulation that the data after, sampling through A/D are at first carried out digital carrier obtains in-phase component and quadrature component, and carrying out the Synchronous Processing of sequence after as the corresponding addition of imaginary part as real part, quadrature component with in-phase component, output sequence is information sequence to be deciphered synchronously; Two, the information sequence for the treatment of deciphering is done by dynamic deciphering parameter-α and is dynamically deciphered the multi-parameter four-item weight class fractional Fourier transform of vector MV, NV control, and the sequence after the conversion is the sequence after the deciphering;

Described multi-parameter four-item weight class fractional Fourier transform is defined as follows:

F ^α[x(n)]＝w ₀(α)x(n)+w ₁(α)X(n)+w ₂(α)x(-n)+w ₃(α)X(-n)

Wherein

L=0,1,2,3

Be by α, MV=[m ₀, m ₁, m ₂, m ₃] and NV=[n ₀, n ₁, n ₂, n ₃] the common weight coefficient of controlling of these 9 parameters, wherein α is any real number, and MV and NV are four-dimensional real vector, and x (n) and X (n) they are that discrete Fourier transform (DFT) is right;

Baseband modulation mode described in the step 1 in ciphering process is MPSK.

In the present invention, on the selection principle of dynamic encryption parameter alpha any real number, but because periodic the existence, α chooses the real number between [0,4] or [2,2] usually.For fixing α, have only the criterion of an optimum to recover original information signal in theory from the signal after encrypting, promptly the signal after encrypting is done the four-item weight class fractional Fourier transform of parameter for-α.Because the flexibility that α selects makes system user to encrypt signal according to the different encryption parameter of actual conditions Dynamic Selection.When selection of parameter is proper, coded signal will present class Gauss's distribution character.

In order to resist of the scanning of non-purpose receiver, introduce dynamic encryption quantity M and N to encryption parameter α.In the definition of four-item weight score Fourier, MV and NV are respectively four-dimensional real vector.(two four-dimensional vectors) can't scan encryption parameter α merely after introducing these eight parameters, further improved the effect of information encryption.When MV and NV got some particular value, the signal after the encryption also can present the characteristic of certain " constellation division ", and promptly the number of constellation points of Ju Jiing is counted many than modulation constellation before encrypting.Utilize this characteristic can confuse non-purpose receiver, make it do the judgement that makes mistake.

Method of the present invention can be encrypted data-signal under the condition of occupying volume external spectrum resource not; The complexity and the fast fourier transformation algorithm of its realization are suitable, and it is less to take system hardware resources, are easy to realize; The core cell of encrypt and decrypt is identical, all is four-item weight class fractional Fourier transform module, so multiplexing when being easy to duplex communication; Can select encryption parameter according to actual conditions, realize dynamic encryption, reliability height, cipher round results are good, be difficult for being detected the modulation system of using by existing algorithm, effectively resisted of the scanning of non-purpose receiver, made non-communication objective person be difficult to intercept and capture and detect signal of communication encryption parameter.

Description of drawings

Fig. 1 is based on the secure communication device structural representation of multi-parameter four-item weight score Fourier conversion, Fig. 2 is the communication encryption modular structure schematic diagram of parallel data processing mode, Fig. 3 is the communication encryption modular structure schematic diagram of serial data processing mode, Fig. 4 is the communication deciphering module structural representation of parallel data processing mode, Fig. 5 is the communication deciphering module structural representation of serial data processing mode, Fig. 6 is the counter-rotating modular structure schematic diagram of serial data processing mode, Fig. 7 is the counter-rotating modular structure schematic diagram of parallel data processing mode, Fig. 8 is that the QPSK signal is at MV=0, planisphere before and after encrypting during NV=0, Fig. 9 are the QPSK signals at M and N is not to present the schematic diagram of " constellation division " characteristic at 0 o'clock entirely.

Embodiment

Embodiment one: present embodiment is described below in conjunction with Fig. 1.Described communication encryption and the decryption method based on multi-parameter four-item weight class fractional Fourier transform of present embodiment realizes by following step: at transmitter terminal, data source is given encrypting module through after the baseband modulation, encrypting module carries out four-item weight class fractional Fourier transform to data under the control of dynamic encryption parameter alpha and dynamic encryption vector MV, NV, send into channel again after D/A conversion and up-conversion through the enciphered data after the digital carrier modulation and transmit; At receiver end, be sent to deciphering module through the data after down-conversion and the A/D sampling, in deciphering module, at first carry out digital carrier coherent demodulation, then through dynamic deciphering parameter-α, dynamically decipher the four-item weight class fractional Fourier transform of vector MV, NV control after, receive data and obtain deciphering, carry out base band demodulating work then.

The concrete steps of encrypting are:

One, the signal to be encrypted that becomes plural form after the binary data process baseband modulation that data source provides gives encrypting module to encrypt, and wherein the baseband modulation mode can be digital modulation modes such as MPSK, MQAM;

Two, encrypting module is encrypted four data sequences respectively simultaneously frame by frame, and the frame length of data sequence is the length of discrete Fourier transform (DFT), chooses 2 integral number power usually, and the user can select flexibly according to actual conditions.The core of encrypting promptly is weighted summation to the data sequence, and four data sequences are followed successively by: sequence after the sequence after the be-encrypted data sequence of input, the be-encrypted data sequence process discrete Fourier transform (DFT), the be-encrypted data sequence process counter-rotating resume module and be-encrypted data sequence are successively through the sequence after discrete Fourier transform (DFT) and the counter-rotating resume module; According to encryption parameter α and dynamic encryption vector MV, the NV of Dynamic Selection, and by coefficient generation module generation weight coefficient w ₀, w ₁, w ₂, w ₃Be weighted summation to being weighted data sequence;

Three, the sequence of complex numbers after the weighting is carried out digital carrier modulation back output, be the signal after the encryption.

In above-mentioned ciphering process, can be digital modulation modes such as MPSK, MQAM in the baseband modulation mode described in the step 1.At the frame length of the data sequence described in the step 2, can select flexibly according to actual conditions.

The concrete steps of deciphering are:

One, after the data that receive is changed through A/D, the coherent demodulation of at first carrying out digital carrier obtains in-phase component and quadrature component, and carrying out the Synchronous Processing of sequence after as the corresponding addition of imaginary part as real part, quadrature component with in-phase component, output sequence is sequence of complex numbers to be deciphered synchronously;

Two, the sequence of complex numbers for the treatment of deciphering is done parameter and is-four-item weight class the fractional Fourier transform of α, MV, NV, and detailed process is identical with ciphering process, and the sequence after the conversion is the sequence after the deciphering, can transfer to the base band demodulating module and carry out next step work.

Embodiment two: specify present embodiment below in conjunction with Fig. 2.Present embodiment is described to be the encrypting module described in the embodiment one, it comprises string and modular converter 1, a counter-rotating module 2, Fourier transform module 3, coefficient generation module 4, No. two counter-rotating modules 5, parallel serial conversion module 7, summation module 6 and digital carrier modulation module 8, serial data stream is input to the input of a counter-rotating module 2 simultaneously, the input of string and modular converter 1 and the reset terminal 40 of coefficient generation module 4, second input 42 of the output coefficient of connection generation module 4 of a counter-rotating module 2, the output of string and modular converter 1 connects the input of Fourier transform module 3, the output of described Fourier transform module 3 connects the input of parallel serial conversion module 7, the input of the first input end 41 of the output coefficient of connection generation module 4 of described parallel serial conversion module 7 and No. two counter-rotating modules 5, the 3rd input 43 of the output coefficient of connection generation module 4 of described No. two counter-rotating modules 5, described coefficient generation module 4 is according to the encryption Control Parameter α and the dynamic encryption vector MV of outside input, NV produces weight coefficient w ₀, w ₁, w ₂, w ₃, four outputs of coefficient generation module 4 connect four inputs of summation module 6 respectively, and the output of described summation module 6 connects the input of digital carrier modulation module 8, the serial data stream after the output output of digital carrier modulation module 8 is encrypted.

Summation module 6 in the present embodiment can adopt adder.

Encrypting module is used for producing the fractional Fourier transform signal based on four-item weight, and wherein Fourier transform module 3 is used the fast algorithm implementation of discrete Fourier transform (DFT).As Fig. 2 and Fig. 3.Wherein discrete Fourier transform (DFT) adopts as gives a definition:

$X\left(k\right)=\frac{1}{\sqrt{N}}\underset{n=0}{\overset{N-1}{\mathrm{\&Sigma;}}}x\left(n\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H2008101369395E00031.png,H2008101369395E00041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}}{N}\mathrm{kn}}.$

Deciphering module is compared with encrypting module, has replaced the central digital carrier modulation module of encrypting module with digital carrier coherent demodulation module, and has increased the sequence synchronization module in order to carry out the synchronous of information sequence, and all the other modules are all identical.As Fig. 4 and Fig. 5.

A counter-rotating module 2 and No. two counter-rotating modules 5 are used for realizing handling the time reversal of list entries.Detailed process is: first element position of list entries is constant, other elements according to from back to front order rearrange the back as output sequence second to last element.As shown in Figure 6 and Figure 7.

The base band data of input encrypting module can be digital modulation signals such as MPSK or MQAM.Baseband modulation/demodulation module can be integrated in simultaneously in a DSP or the fpga chip with encrypting-decrypting module and realize.

Embodiment three: specify present embodiment below in conjunction with Fig. 3.Present embodiment is described to be the encrypting module described in the embodiment one, it comprises string and modular converter 1, a counter-rotating module 2, Fourier transform module 3, coefficient generation module 4, No. two counter-rotating modules 5, parallel serial conversion module 7, summation module 6 and digital carrier modulation module 8, serial data stream is input to the input of a counter-rotating module 2 simultaneously, the input of string and modular converter 1 and the reset terminal 40 of coefficient generation module 4, second input 42 of the output coefficient of connection generation module 4 of a counter-rotating module 2, the output of string and modular converter 1 connects the input of Fourier transform module 3, the output of described Fourier transform module 3 connects the input of parallel serial conversion module 7, the input of the first input end 41 of the output coefficient of connection generation module 4 of described parallel serial conversion module 7 and No. two counter-rotating modules 5, the 3rd input 43 of the output coefficient of connection generation module 4 of described No. two counter-rotating modules 5, described coefficient generation module 4 is according to the encryption Control Parameter α and the dynamic encryption vector MV of outside input, NV produces weight coefficient w ₀, w ₁, w ₂, w ₃, four outputs of coefficient generation module 4 connect four inputs of summation module 6 respectively, and the output of described summation module 6 connects the input of digital carrier modulation module 8, the serial data stream after the output output of digital carrier modulation module 8 is encrypted.

Embodiment four: specify present embodiment below in conjunction with Fig. 4.Present embodiment is described to be the deciphering module described in the embodiment one, it comprises string and modular converter 1, digital carrier coherent demodulation module 18, a counter-rotating module 2, Fourier transform module 3, coefficient generation module 4, No. two counter-rotating modules 5, sequence synchronization module 19, parallel serial conversion module 7 and summation module 6, serial data stream is input to the input of string and modular converter 1, the output of described string and modular converter 1 connects the input of digital carrier coherent demodulating module 18, the input of the output catenation sequence synchronization module 19 of described digital carrier coherent demodulation module 18, the output of described sequence synchronization module 19 connects the input of Fourier transform module 3 respectively, the input of a counter-rotating module 2 and the reset terminal 40 of coefficient generation module 4, second input 42 of the output coefficient of connection generation module 4 of a described counter-rotating module 2, the first input end 41 of the output difference coefficient of connection generation module 4 of described Fourier transform module 3 and the input of No. two counter-rotating modules 5, the 3rd input of the output coefficient of connection generation module 4 of described No. two counter-rotating modules 5, described coefficient generation module 4 is according to deciphering Control Parameter-α that receives and dynamic deciphering vector MV, NV produces weight coefficient w ₀, w ₁, w ₂, w ₃, four outputs of coefficient generation module 4 connect four inputs of summation module 6 respectively, and the output of described summation module 6 connects the input of parallel serial conversion module 7, the serial data stream after the output output deciphering of parallel serial conversion module 7.

Embodiment five: specify present embodiment below in conjunction with Fig. 5.Present embodiment is described to be the deciphering module described in the embodiment one, it comprises string and modular converter 1, digital carrier coherent demodulation module 18, a counter-rotating module 2, Fourier transform module 3, coefficient generation module 4, No. two counter-rotating modules 5, sequence synchronization module 19, parallel serial conversion module 7 and summation module 6, serial data stream is input to the input of digital carrier coherent demodulation module 18, the input of the output catenation sequence synchronization module 19 of described digital carrier coherent demodulation module 18, the output of described sequence synchronization module 19 connects the input of string and modular converter 1 respectively, the input of a counter-rotating module 2 and the reset terminal 40 of coefficient generation module 4, second input 42 of the output coefficient of connection generation module 4 of a described counter-rotating module 2, the output of described string and modular converter 1 connects the input of Fourier transform module 3, the output of described Fourier transform module 3 connects the input of parallel serial conversion module 7, the first input end 41 of the output difference coefficient of connection generation module 4 of described parallel serial conversion module 7 and the input of No. two counter-rotating modules 5, the 3rd input 43 of the output coefficient of connection generation module 4 of described No. two counter-rotating modules 5, four outputs of described coefficient generation module 4 connect four inputs of summation module 6 respectively, the serial data stream after the output output deciphering of described summation module 6.

Communication encryption module of the present invention and deciphering module all can be united realization by DSP, FPGA or FPGA and DSP.

Communication encryption module of the present invention and deciphering module can adopt the system configuration of parallel data processing mode or serial data processing mode, wherein the structure of parallel data processing mode is more suitable in adopting FPGA to realize that the structure of serial data processing mode is more suitable for adopting DSP to realize; If adopt FPGA associating DSP or other hardware structures, then can be according to the suitable Adjustment System structure of actual conditions.

Claims (4)

1. based on the communication encryption and the decryption method of multi-parameter four-item weight class fractional Fourier transform, it is characterized in that at transmitter terminal, data source is fed to encrypting module through after the baseband modulation, encrypting module carries out multi-parameter four-item weight class fractional Fourier transform to obtain enciphered data to data under the control of dynamic encryption parameter alpha and dynamic encryption vector MV, NV, send into channel again after D/A conversion and up-conversion through the enciphered data after the digital carrier modulation and transmit; At receiver end, be sent to deciphering module through the data after down-conversion and the A/D sampling, in deciphering module, at first carry out digital carrier coherent demodulation, then after multi-parameter four-item weight class fractional Fourier transform through dynamic deciphering parameter-α and dynamically deciphering vector MV, NV control, receive data and obtain deciphering, carry out base band demodulating work then; The concrete steps of encrypting are: the signal to be encrypted that, becomes plural form after the binary data process baseband modulation that data source provides gives encrypting module to encrypt; Two, encrypting module is encrypted data frame by frame, and frame length is the length of discrete Fourier transform (DFT); The core of encrypting promptly is weighted summation to the data sequence, and four sequences that are weighted are followed successively by: the sequence after the sequence after the be-encrypted data sequence of input, the be-encrypted data sequence process discrete Fourier transform (DFT), the be-encrypted data sequence process counter-rotating module, be-encrypted data sequence are successively through the sequence after discrete Fourier transform (DFT) and the counter-rotating module; User's Dynamic Selection dynamic encryption parameter alpha and dynamic encryption vector MV, NV, and by coefficient generation module generation weight coefficient w ₀, w ₁, w ₂, w ₃, be weighted summation to being weighted sequence; Three, the sequence of complex numbers after the weighting is carried out digital carrier modulation back output, be the sequence after the encryption; The concrete steps of deciphering are: the coherent demodulation that the data after, sampling through A/D are at first carried out digital carrier obtains in-phase component and quadrature component, and carrying out the Synchronous Processing of sequence after as the corresponding addition of imaginary part as real part, quadrature component with in-phase component, output sequence is information sequence to be deciphered synchronously; Two, the information sequence for the treatment of deciphering is done by dynamic deciphering parameter-α and is dynamically deciphered the multi-parameter four-item weight class fractional Fourier transform of vector MV, NV control, and the sequence after the conversion is the sequence after the deciphering;

Described multi-parameter four-item weight class fractional Fourier transform is defined as follows:

F ^α[x(n)]＝w ₀(α)x(n)+w ₁(α)X(n)+w ₂(α)x(-n)+w ₃(α)X(-n)

Wherein $w_l\left(\mathrm{\&alpha;}\right)=\frac{1}{4}\underset{k=0}{\overset{3}{\mathrm{\&Sigma;}}}\exp \{\&PlusMinus;\frac{2\mathrm{\&pi;i}}{4}[({4m}_k+1)\mathrm{\&alpha;}(k+4n_k)-\mathrm{lk}\left]\right\},l=\mathrm{0,1,2,3}$

Be by α, MV=[m ₀, m ₁, m ₂, m ₃] and NV=[n ₀, n ₁, n ₂, n ₃] the common weight coefficient of controlling of these 9 parameters, wherein α is any real number, and MV and NV are four-dimensional real vector, and x (n) and X (n) they are that discrete Fourier transform (DFT) is right;

Baseband modulation mode described in the step 1 in ciphering process is MPSK.

2. communication encryption and decryption method based on multi-parameter four-item weight class fractional Fourier transform according to claim 1, it is characterized in that described encrypting module comprises string and modular converter (1), a counter-rotating module (2), Fourier transform module (3), coefficient generation module (4), No. two counter-rotating modules (5), parallel serial conversion module (7), summation module (6) and digital carrier modulation module (8), serial data stream is input to the input of a counter-rotating module (2) simultaneously, the input of string and modular converter (1) and the reset terminal (40) of coefficient generation module (4), second input (42) of the output coefficient of connection generation module (4) of a counter-rotating module (2), the output of string and modular converter (1) connects the input of Fourier transform module (3), the output of described Fourier transform module (3) connects the input of parallel serial conversion module (7), the input of the first input end (41) of the output coefficient of connection generation module (4) of described parallel serial conversion module (7) and No. two counter-rotating modules (5), the 3rd input (43) of the output coefficient of connection generation module (4) of described No. two counter-rotating modules (5), described coefficient generation module (4) is according to the dynamic encryption parameter alpha and the dynamic encryption vector MV of outside input, NV produces weight coefficient w ₀, w ₁, w ₂, w ₃Four outputs of coefficient generation module (4) connect four inputs of summation module (6) respectively, the output of described summation module (6) connects the input of digital carrier modulation module (8), the serial data stream after the output output of digital carrier modulation module (8) is encrypted.

3. communication encryption and decryption method based on multi-parameter four-item weight class fractional Fourier transform according to claim 1, it is characterized in that described deciphering module comprises string and modular converter (1), digital carrier coherent demodulation module (18), a counter-rotating module (2), Fourier transform module (3), coefficient generation module (4), No. two counter-rotating modules (5), sequence synchronization module (19), parallel serial conversion module (7) and summation module (6), serial data stream is input to the input of string and modular converter (1), the output of described string and modular converter (1) connects the input of digital carrier coherent demodulating module (18), the input of the output catenation sequence synchronization module (19) of described digital carrier coherent demodulation module (18), the output of described sequence synchronization module (19) connects the input of Fourier transform module (3) respectively, the input of a counter-rotating module (2) and the reset terminal (40) of coefficient generation module (4), second input (42) of the output coefficient of connection generation module (4) of a described counter-rotating module (2), the first input end (41) of the output difference coefficient of connection generation module (4) of described Fourier transform module (3) and the input of No. two counter-rotating modules (5), the 3rd input of the output coefficient of connection generation module (4) of described No. two counter-rotating modules (5), described coefficient generation module (4) is according to dynamic deciphering parameter-α that receives and dynamic deciphering vector MV, NV produces weight coefficient w ₀, w ₁, w ₂, w ₃Four outputs of coefficient generation module (4) connect four inputs of summation module (6) respectively, the output of described summation module (6) connects the input of parallel serial conversion module (7), the serial data stream after the output output deciphering of parallel serial conversion module (7).

4. communication encryption and decryption method based on multi-parameter four-item weight class fractional Fourier transform according to claim 1, it is characterized in that described deciphering module comprises string and modular converter (1), digital carrier coherent demodulation module (18), a counter-rotating module (2), Fourier transform module (3), coefficient generation module (4), No. two counter-rotating modules (5), sequence synchronization module (19), parallel serial conversion module (7) and summation module (6), serial data stream is input to the input of digital carrier coherent demodulation module (18), the input of the output catenation sequence synchronization module (19) of described digital carrier coherent demodulation module (18), the output of described sequence synchronization module (19) connects the input of string and modular converter (1) respectively, the input of a counter-rotating module (2) and the reset terminal (40) of coefficient generation module (4), second input (42) of the output coefficient of connection generation module (4) of a described counter-rotating module (2), the output of described string and modular converter (1) connects the input of Fourier transform module (3), the output of described Fourier transform module (3) connects the input of parallel serial conversion module (7), the first input end (41) of the output difference coefficient of connection generation module (4) of described parallel serial conversion module (7) and the input of No. two counter-rotating modules (5), the 3rd input (43) of the output coefficient of connection generation module (4) of described No. two counter-rotating modules (5), four outputs of described coefficient generation module (4) connect four inputs of summation module (6) respectively, the serial data stream after the output output deciphering of described summation module (6).

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